The present invention relates generally to packages for use in microwave ovens, pertains particularly to an easily expandable, nontrapping, flexible, microwave package formed of non-extendable material for the popping, puffing or expanding of food products and especially popcorn kernels, and pertains more particularly to a microwave package providing serving bowl and/or easy open features.
To conserve space during shipping and storage, microwave popcorn packages are often folded flat. During popping by use of microwave energy, the popcorn package expands, with the expansion due to the internal pressure of the steam produced by the popping of the popcorn kernels and evaporation of the water content of the flavoring slurry, the pressure of the popped kernels themselves, as well as other factors. An important feature for maximizing the volume of the popped kernels is the ability of the microwave popcorn package to easily expand. Another important factor for maximizing the volume of the popped kernels is that the number of kernels which are actually popped be maximized by insuring that the unpopped kernels are located together on the susceptor with sufficient dwell time to receive sufficient heat energy to result in popping. The shape of the bag plays an important role in the ability of the bag to expand as well as the ability of unpopped kernels to come in contact with each other and the susceptor before and during popping.
One form of conventional popcorn packages is a bag having a rectangular top, a rectangular bottom and pleated sides and with at least one end being sealed together by attaching the top and bottom together such as but not limited to by folding the end of the bag over onto itself. It is a common problem for unpopped kernels to be propelled in the popping process into folds and crevices in the bag and especially those created by the pleats in the sides adjacent to the end(s) of the bag. Such kernels may tend to be captured in such folds and crevices so that they are unable to travel towards the susceptor and are less likely to be popped during microwave cooking.
Further, conventional rectangular popcorn bags tend to get hung up in the corners of the microwave ovens. This is undesirable for microwave ovens including turntables as the bag will no longer rotate inside of the microwave cavity but is locked in position by the corner. However, even for microwave ovens which are not equipped with turntables, the expansion of the bag and/or the vibration of the bag caused by the popping of the popcorn kernels do not result in moving the bag to the center of the microwave cavity when the bag gets hung up in a corner of the microwave cavity. This is undesirable as cooler spots typically exist in the corners of the microwave cavity and as lack of movement of the bag subjects certain points in the bag to see specific hot spots or electronic nulls.
Thus, a need continues to exist for an improved flexible paper popcorn package which is easily expandable by the dynamics involved in popping the kernels, which is less likely to capture unpopped kernels during the expansion of the package while subjected to microwave energy, and which provides the most consistent and uniform distribution of microwave energy in maximizing the number and volume of popped popcorn. In further aspects of the present invention, the popcorn package which is utilized to pop the popcorn kernels has the ability to be utilized as the serving bowl during consumption of the popped kernels. In still other aspects of the present invention, the expanded popcorn package can be easily opened by the consumer with minimal instructions.
Surprisingly, the above need and other objectives can be satisfied by providing, in the preferred form, an expandable microwave package in the form of a bag formed by top and bottom walls of flexible, non-extendable material interconnected together adjacent to their substantially round or round-like shaped outer peripheries so that the top and bottom walls expand into an opposing double domed shape when the food products are popped, puffed or expanded in the microwave oven.
In a most preferred form, the top wall is fabricated from multiple layers and includes a first annular portion having an access opening and a closure portion of a size greater than the access opening and interconnected to the first portion by a seal, with the access opening, closure portion, and seal being oval in shape. In most preferred aspects, the seal is of the cold seal type formed of natural rubber and isoprene and/or synthetic copolymers and which fails during microwave cooking, allowing trapped steam to vent and allowing the removal of the closure portion to provide access to the popped, puffed or expanded food product. Also, in most preferred aspects, an extension is formed on the outer periphery of the closure portion and extending in line with the major axis of the oval shape for grasping when removing the closure portion.
In other preferred aspects of the present invention, the bag formed by the interconnection of top and bottom walls having round-like shaped outer peripheries is folded about first and second, parallel, fold lines located on opposite sides of the generally oval shaped closure panel so the seal between the annular and closure portions are not subjected to a hard fold. The bag is then folded about a third fold line extending perpendicularly between the first and second fold lines at which time the food products are introduced through the periphery interconnection portion which is then sealed, and then folded about a fourth fold line extending parallel to the third fold line, with the folded bag having a conventional, rectangular shape for secondary packaging.
In still other preferred aspects, extensions are formed on the outer peripheries of the top and bottom walls outward of the interconnection, with the consumer grasping the extensions for removing the bag from the microwave oven, for carrying the bag, and for opening the bag. In preferred aspects, the extensions of the top and bottom walls are in line with the extension of the closure panel of a multiple layer top wall for ease of removal of the closure panel. For other preferred aspects, the extensions extend on diametrically opposite sides of the bag for providing optimal gripping by two hands when the bag is utilized as a serving bowl.
In preferred forms of the present invention, slits are formed in the extensions for relieving constraints to the puckering of the walls of the bag as the bag expands when the food product pops, puffs or expands. In preferred aspects of the present invention, the slits can be expanded to define an opening, can be spaced inwardly from or can intersect the extension outer edge, and/or can include scrolled ends.